In my earlier U.S. Pat. No. 5,931,839, there is disclosed an implantable fixation device which comprises a K-wire or pin for fixation of a bone fracture and a fixation plate for engaging the end of the pin which extends from the bone structure. In the patent, the protruding end of the pin is engaged in a hole in the fixation plate such that the pin is free to axially travel in the hole. In order to prevent separation of the pin from slipping out of from under the hole in the plate, the end of the pin can be bent while preserving the axial sliding capability of the pin in the hole in the plate.
Single K-wire fixation of bone fragments does not provide secure fixation, since the K-wire is secured only at a single end that can be at a considerable distance from the fracture site. The fixation or pin plate provides fixation of the K-wire at a second site, but has the disadvantage of requiring the K-wire to be bent over the edge of the plate or into an adjacent hole in the plate. This step requires backing out of the K-wire and is cumbersome and can lose reduction.
In addition, current pin plate designs allow the pin to back out with motion of the fracture. This can lead to abrasion of adjacent soft tissue structures and even tendon rupture.